80 research outputs found

    Design and Development of Hand and Foot Contamination Monitor

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    A hand and foot contamination monitor is a health physics instrument to provide detection and measurement of beta-gamma contamination on the palm of each hand and on the bottom surface of both feet/shoes. There are four channels of detection for two hands and two feet. Four G-M detectors have been used in a single unit to cover the whole area of hand and feet. A regulated high voltage DC power supply (900 V) has been designed using the PIC12F675 microcontroller to operate the pancake Geiger-Müller detectors. The reading is displayed on a linearly scaled 0-100 Bq/cm2 analog panel meter. The monitor detects beta–gamma radiation emitted by radioactive materials, and if the detected value exceeds a preset level, the monitor sounds an alarm and displays a reading in the respective panel meter. Indicator lamps are used to show the status of contamination. The performance of the system has been tested by using pulse generator and by flat surface radioactive calibration sources. Electronic linearity, detection efficiency, response to the contamination, calibration factor and percentage of error has been measured. Test results were satisfactory and the present system can be used instead of similar imported instruments. Received: 21 May 2014; Revised: 21 August 2014; Accepted: 22 August 201

    Design and Development of Hand and Foot Contamination Monitor

    Get PDF
    A hand and foot contamination monitor is a health physics instrument to provide detection and measurement of beta-gamma contamination on the palm of each hand and on the bottom surface of both feet/shoes. There are four channels of detection for two hands and two feet. Four G-M detectors have been used in a single unit to cover the whole area of hand and feet. A regulated high voltage DC power supply (900 V) has been designed using the PIC12F675 microcontroller to operate the pancake Geiger-Müller detectors. The reading is displayed on a linearly scaled 0-100 Bq/cm2 analog panel meter. The monitor detects beta–gamma radiation emitted by radioactive materials, and if the detected value exceeds a preset level, the monitor sounds an alarm and displays a reading in the respective panel meter. Indicator lamps are used to show the status of contamination. The performance of the system has been tested by using pulse generator and by flat surface radioactive calibration sources. Electronic linearity, detection efficiency, response to the contamination, calibration factor and percentage of error has been measured. Test results were satisfactory and the present system can be used instead of similar imported instruments. Received: 21 May 2014; Revised: 21 August 2014; Accepted: 22 August 201

    Elemental Study of Bangladeshi Fish Samples Using PIGE Technique

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    Proton induced gamma emission (PIGE) method has been developed at the Accelerator Laboratory of Atomic Energy Center, Dhaka (AECD) for the investigation of various human health related specimens. In the present study PIGE analytical technique has been used for the determination of numerous trace elements in some commonly used fish samples which were collected from Islampur area at Savar. During the experimental work the γrays emitted from the prepared fish samples were measured using a Highpurity Germenium (HPGe) detector. The detected 18 elements were Iron, Calcium, Sodium, Magnesium, Aluminum, Potassium, Vanadium, Chromium, Manganese, Copper, Zinc, Selenium, Bromine, Rubidium, Strontium, Cadmium, Iodine, Lead etc. The objective of this study was to measure the concentrations of these trace elements in the collected fish samples and to investigate whether their concentrations are harmful for human health by comparison with limits set by WHO/FAO. The results obtained indicate that Fe, K and Ca concentrations were relatively high in all samples as compared with the other elements. The measured elemental concentration of Fe, Mn, Zn, Cu, Cr and V in all fish samples were found to be above the WHO/FAO recommended limits

    The impact of policy modifiable factors on inequalities in rates of child dental caries in Australia

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    Background: Poor oral health in childhood can lead to adverse impacts later in life. We aimed to estimate the prevalence and population distribution of childhood dental caries in Australia and investigate factors that might ameliorate inequalities. Methods: Data from the nationally representative birth cohort Longitudinal Study of Australian Children (N = 5107), using questions assessing: The experience of dental caries during each biennial follow-up period (2-3 years to 10-11 years), socioeconomic position (SEP), and policy modifiable oral health factors. Results: The odds of dental caries were higher for children with lowest vs. highest SEP (adjusted OR (adjOR) 1.92, 95% CI 1.49-2.46), and lower where water was fluoridated to recommended levels (adjOR 0.53, 95% CI 0.43-0.64). There was no evidence of an association between caries experience and either reported sugary diet or tooth brushing. When SEP and fluoridation were considered in conjunction, compared to the highest SEP group with water fluoridation children in the lowest SEP with fluoridation had adjOR 1.54 for caries, (95% CI 1.14-2.07), and children in the lowest SEP without fluoridation had adjOR 4.06 (95% CI 2.88-5.42). For patterns of service use: The highest SEP group reported a greater percentage of service use in the absence of caries. Conclusions: Dental caries appears prevalent and is socially distributed in Australia. Policy efforts should consider how to ensure that children with dental caries receive adequate prevention and early care with equitable uptake.Sharon Goldfeld, Kate Louise Francis, Monsurul Hoq, Loc Do, Elodie O’Connor, and Fiona Mensa

    Bose-Hubbard model with occupation dependent parameters

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    We study the ground-state properties of ultracold bosons in an optical lattice in the regime of strong interactions. The system is described by a non-standard Bose-Hubbard model with both occupation-dependent tunneling and on-site interaction. We find that for sufficiently strong coupling the system features a phase-transition from a Mott insulator with one particle per site to a superfluid of spatially extended particle pairs living on top of the Mott background -- instead of the usual transition to a superfluid of single particles/holes. Increasing the interaction further, a superfluid of particle pairs localized on a single site (rather than being extended) on top of the Mott background appears. This happens at the same interaction strength where the Mott-insulator phase with 2 particles per site is destroyed completely by particle-hole fluctuations for arbitrarily small tunneling. In another regime, characterized by weak interaction, but high occupation numbers, we observe a dynamical instability in the superfluid excitation spectrum. The new ground state is a superfluid, forming a 2D slab, localized along one spatial direction that is spontaneously chosen.Comment: 16 pages, 4 figure

    Enzymatic glyceride synthesis in a foam reactor

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    We report the results of our study on Rhizomucor miehei lipaseâ catalyzed lauric acidâ glycerol esterification in a foam reactor. A satisfactory yield of glyceride synthesis can be achieved with an unusually high initial water content (50% w/w). We found that product formation could be regulated by controlling foaming. Foaming was a function of the air flow rate, reaction temperature, pH value, ionic strength, and substrate molar ratio. Monolaurin and dilaurin, which constituted nearly 80% of the total yield, were the two dominant products in this reaction; trilaurin was also formed at the initial stages of the reaction. A study of pH and ionic strength effects on an independent basis revealed that they affect the interfacial mechanism in different manners. On varying the ratio of lauric acid and glycerol, only a slight change in the degree of conversion was detected and the consumption rate of fatty acid was approximately the same.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141443/1/aocs0643.pd

    Characterisation of the MALT90 Survey and the Mopra Telescope at 90 GHz

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    We characterise the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90) and the Mopra telescope at 90 GHz. We combine repeated position-switched observations of the source G300.968+01.145 with a map of the same source in order to estimate the pointing reliability of the position-switched observations and, by extension, the MALT90 survey; we estimate our pointing uncertainty to be 8 arcsec. We model the two strongest sources of systematic gain variability as functions of elevation and time-of-day and quantify the remaining absolute flux uncertainty. Corrections based on these two variables reduce the scatter in repeated observations from 12%–25% down to 10%–17%. We find no evidence for intrinsic source variability in G300.968+01.145. For certain applications, the corrections described herein will be integral for improving the absolute flux calibration of MALT90 maps and other observations using the Mopra telescope at 90 GHz

    MALT90: The Millimetre Astronomy Legacy Team 90 GHz Survey

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    The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on- the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope∗ , MALT90 has obtained 3′ × 3′ maps toward _2000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to HII regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38) and spectral (0.11 km s−1) resolution, the data reveal a wealth of information about the clump’s morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high resolution studies with ALMA

    Xylanase and β-xylosidase production by Aspergillus ochraceus: new perspectives for the application of wheat straw autohydrolysis liquor

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    The xylanase biosynthesis is induced by its substrate—xylan. The high xylan content in some wastes such as wheat residues (wheat bran and wheat straw) makes them accessible and cheap sources of inducers to be mainly applied in great volumes of fermentation, such as those of industrial bioreactors. Thus, in this work, the main proposal was incorporated in the nutrient medium wheat straw particles decomposed to soluble compounds (liquor) through treatment of lignocellulosic materials in autohydrolysis process, as a strategy to increase and undervalue xylanase production by Aspergillus ochraceus. The wheat straw autohydrolysis liquor produced in several conditions was used as a sole carbon source or with wheat bran. The best conditions for xylanase and β-xylosidase production were observed when A. ochraceus was cultivated with 1% wheat bran added of 10% wheat straw liquor (produced after 15 min of hydrothermal treatment) as carbon source. This substrate was more favorable when compared with xylan, wheat bran, and wheat straw autohydrolysis liquor used separately. The application of this substrate mixture in a stirred tank bioreactor indicated the possibility of scaling up the process to commercial production.This work was supported by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP/Brazil), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq/Brazil), National System for Research on Biodiversity (SISBIOTA-Brazil, CNPq 563260/2010-6/FAPESP no. 2010/52322-3), and Fundacao para a Ciencia e a Tecnologia (FCT/Portugal)
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